Process for sequestering metal ions

ABSTRACT

A process is disclosed for sequestering metal ions by treating said ions with a compound of the formula: ##EQU1## wherein R&#39; is selected from the group consisting of  -OH , alkyloxy and aryloxy; and R is selected from the group consisting of ##EQU2## wherein Z is  -OH , alkyl, aryl, alkoxy and aryloxy.

BACKGROUND OF THE INVENTION

The use of complexing agents which combine with metal ions in solutionto form soluble complexes (which agents are commonly referred to assequestrants) is of great importance in many industrial processesinasmuch as it may prevent undesired precipitation reactions fromoccurring. For example, sequestration of calcium is important in watertreatment and in laundry solutions for controlling hardness of thewater. Sequestration of the heavy metals such as copper and nickel isessential in such areas as textile processing, metal cleaning andfinishing. Not all sequestrants, however, are equally effective, theiractivity varying with their structures and the conditions under whichthey are used, for example, the common carboxylic acid sequestrants areoften ineffective in preventing ferric ion precipitation from alkalinesolutions of pH greater than 8.

The commercial utilization of water-soluble chelating compounds inagricultural applications to provide trace elements for plant growth iswell known. Likewise, the treatment of plants suffering from chlorosisas a result of growth in alkaline soils devoid of sufficientassimilatable iron is known. Various chelating agents have been employedin the past to correct iron deficiencies in plants, the water solubilityof chelated metal ions affords a primary route for potentialassimilation into a plant structure.

Ethylenediaminetetraacetic acid (EDTA) has been employed in the past fortreatment of iron deficiencies of citrus trees under acid conditions.The EDTA iron chelates are not stable in neutral and alkaline media. Thedevelopment of sequestrants which may be employed in acid media as welas alkaline media is significant not only for agricultural applications,but for use in the detergent field, metal cleaning field, textile anddye industry and as stabilizers for organic and inorganic peroxides.

The use of the sequestrants in sulfite baths for the electrodepositionof gold and gold alloys as additives for improving the performances andthe operating conditions of said baths is also of high importance. Ingeneral, additives which will strongly limit, during electrolysis, theinfluence on the quality of the deposits of the variations of someoperating factors, such as temperature, pH of the bath, current density,type and degree of agitation, etc., are desirable. It is well known inthe art of electrodepositing gold and gold alloys from sulfite bathsthat the above operating factors normally have a strong influence on thenature and the properties of the coatings obtained. Thus, it is oftennecessary to accurately control some of said factors in order to obtaindeposits having the properties required (color, ductility, gloss, etc.).Most often, relatively slight variations of current density result inthe formation of foggy deposits, burns, pittings or color changes,particularly when depositing gold alloys. The introduction of theinstant compounds into sulfite gold baths largely prevents thesedifficulties. In the presence of such additives, it is possible to varyoperational factors between relatively wide limits without affecting thequality of the coatings and, in the case of gold alloys, withoutappreciably modifying the composition and the carat thereof. Theprinciple of action of these additives is not known exactly; it is,however, possible that they may standardize the electrochemicalproperties of the various metals which are plated simultaneously, e.g.,the electrodeposition potential and the distribution of ions in thecathode layer.

Further, many flame retarding agents and methods of application havebeen developed in attempts to obtain flame resistant textile materialsand thermoplastic resin compositions.

Flame retardant textiles have been produced by depositing metal oxides,within or on the textile fibers, by the successive precipitation offerric oxides and a mixture of tungstic acid and stannic oxide or bysuccessive deposition of antimony trioxide and titanium dioxide. Suchprocesses require plural treatment baths in which strongly acidicsolutions are employed, thus posing the problem of possible textiledegradation. Furthermore, metal oxide coatings on textile materialscreate difficulties in subsequent dyeing processes which deleteriouslyaffect the hand of the finished product. Other processes involve the useof a single processing bath wherein a dispersion of chlorinatedhydrocarbon and finely divided antimony oxide is padded on the textilematerial. Near the textile combustion temperature, antimony oxide willreact with hydrogen chloride, generated by degradation of thechlorinated hydrocarbon, to form antimony oxychloride which acts tosuppress flame. This combination of a chlorinated hydrocarbon and finelydivided antimony oxide are not acceptable finishes for closely woventextiles as they deleteriously affect the hand of the finished product.A further process for imparting flame resistance to cellulosic materialsis by the esterification of the cellulose with diammonium hydrogenortho-phosphate. Textile products so treated, however, are subjected tometathesis reaction with cations during washing, and must be regeneratedby reacting the wash product with an ammonium chloride solution.

The production of thermoplastic resin compositions which are flameretardant is of considerable commercial importance. For example, sucharticles as castings, moldings, foamed or laminated structures and thelike are required, or are at least desired, to be resistant to fire andflame and to possess the ability to endure heat without deterioration.The use of various materials incorporated into thermoplastic resins soas to improve the flame retardancy thereof has been known. Manycompounds have been commercially available for such use, among thembeing chlorostyrene copolymers, chlorinated paraffin wax in admixturewith triphenyl styrene, chlorinated paraffins and aliphatic antimonicalcompounds, as well as antimony oxide-chlorinated hydrocarbon mixtures. Aproblem associated with these compounds has been, however, the fact thatgenerally a large amount, i.e., upwards to 35% of additive, must beincorporated into the resin in order to make it sufficiently flameretardant. Such large amounts of additive may deleteriously affect thephysical characteristics of the thermoplastic resin, as well assubstantially complicating and increasing the cost of preparationthereof. A further problem is that these prior art additives tend tocrystallize or oil out of the resin after a relatively short time ofincorporation. The present invention relates to a group of compoundswhich may be added to thermoplastic resins in relatively small amountsand still produce satisfactory flame retardant compositions which willnot crystallize nor oil out of the resin after incorporation therein.

OBJECTS OF THE INVENTION

It is, therefore, a principal object of this invention to provide novelcompounds of the formula: ##STR1## wherein R' is selected from the groupconsisting of ^(-OH), alkoxy and aryloxy; and R is selected from thegroup consisting of: ##STR2## wherein Z is ^(-OH), alkyl, aryl, alkoxyand aryloxy; provided when R' is ##STR3##

Another object is to provide a method for treating normally flammablecellulosic, proteinaceous or analogous man-made materials to render themflame retardant. Another object is to produce a flame retardant additivewhich chemically combines with the material being treated. Anotherobject is to provide flame retarding thermoplastic resin compositionscomprising normally flammable thermoplastic resin materials. A furtherobject is to provide a process for treating normally flammablethermoplastic resin compositions to render them flame retardant. Aparticular object is to devise a composition comprising normallyflammable cellulosic, proteinaceous or analogous man-made materials andan effective flame retardant amount of the compound represented by theformula: ##STR4## wherein R and R' are as above described. Furthermore,in accordance with the instant invention, there is provided a processfor sequestering metal ions from aqueous solution by reacting thesequestrant mixture of this invention with metal ions. Also, thisinvention provides novel compositions of matter comprising thesequestered metal ion derivatives of the sequestrant mixtures of thisinvention. Still furthermore, an object of this invention is to providean additive useful in improving the electrodeposition of precious metalsin electrochemical deposition process.

These and other objects of the present invention will be obvious fromthe following description.

SUMMARY OF THE INVENTION

It has been discovered that certain compounds have unexpected utility asflame retardant additives and metal ion sequestrants. In accordancetherewith, the instant invention relates to compounds of the formula:##STR5## wherein R' is selected from the group consisting of ^(-OH),alkoxy, preferably of 1-6 carbon atoms, and aryloxy, and R is selectedfrom the group consisting of: ##STR6## wherein Z is selected from thegroup consisting of ^(-OH), alkyl and alkoxy, preferably of 1-6 carbonatoms, aryl and aryloxy, and their use as metal ion sequestrants andflame retardant additives.

Illustrative examples of compounds of the present invention include, forinstance, compounds of the structure: ##SPC1##

The synthesis of the compounds of the instant invention may beaccomplished by various processes. Compounds of the type: ##STR7##wherein Z and R' are as previously described, may be prepared byreacting corresponding N-hydroxy methyl amides, N-hydroxy methylsulfonamides and methylolated ureas of the formulae: ##STR8## wherein Zis as previously described, providing it is not OH⁻, with astoichiometric or excess amount of trialkyl phosphite in a suitablesolvent, or neat, to form intermediate compounds of the formulae:##STR9## wherein R" is alkyl. Typically, the reaction occurs at elevatedtemperatures and is continued for about 1 to about 12 hours.Temperatures are generally from about 50° C to about 160° C. Preferably,the reaction is continued from about 3 to about 6 hours at a temperatureof about 80° C to about 120° C. The solvent or other volatile matter is,thereafter, stripped or otherwise removed from the product. Suitablesolvents include benzene, toluene, xylene, glymes, N-N-dimethylformamide, and aliphatics or aromatic hydrocarbons. Alternately, thecorresponding N-hydroxy methyl amide, N-hydroxy methyl sulfonamide andmethylolated urea starting materials may be reacted with a phosphorustrihalide by the method of U.S. Pat. No. 2,304,156 to form thedihalogenated, phosphonate or diphosphonate intermediate. The dialkylphosphonate or dihalogenated phosphonate intermediate may then beselectively hydrolyzed to provide the final compounds.

Typical compounds suitable as reactants herein include: ##SPC2##

The metal ions which may be sequestered by the composition of thisinvention are those cations having a valence of two or more, such as theions of calcium, chromium, copper, nickel, tin, aluminum, cobalt,platinum, palladium, rhodium, iridium, ruthenium, osmium, zirconium,hafnium, the rare earths such as gadolinium, europium, neodymium, theactinides such as uranium, and iron.

The compounds of this invention, when added to those solutions in whichsequestration is desired, may be added as a solid or as a solution. Ifit is desired to add said compounds as a solution, the compound may bedissolved in water. From about 0.001 percent to about 50 percentconcentration (by weight) may be used, though it is preferred to usefrom about 0.01 to about 5 percent concentration (by weight), and it iseven more preferred to use from about 0.1 to about 3 percentconcentration (by weight).

It is preferred to use said compounds as sequestrants in aqueoussolutions. When said composition is added to the solution containingmetal ions to be sequestered, the temperature of said solution may befrom about 0° to about 100° centigrade, though it is preferred that saidtemperature be from about 20° to about 70° centigrade, and it is evenmore preferred that said solution be at ambient temperature.

The compounds of this invention are preferably used as additives insulfite baths for the electrodeposition of gold and gold alloys. Theycan comprise one or more phosphorus atoms and the acid functions thereofcan be free, esterified partially or completely. It has been found thatin many cases the esters are as active or more active than thecorresponding free acids when added to gold baths and this observationis very surprising and completely unexpected. Indeed, if, as it isgenerally supposed, the activity of the free acid additives is due tothe affinity between the acid OH functions and the metal ions dissolvedin the bath, it is difficult to understand how the ester functions whichshould be relatively inert can even be more active. It should also benoted that the carbonyl derivatives of the present organo-phosphoruscompounds are particularly active.

The effective quantities of the compounds useful according to theinvention can vary between wide limits. These quantities depend,naturally, on the chemical structure of the phosphorus compoundconsidered, that is on the nature and the number of the functionalgroups and, presumably, on their orientation. In some cases, a few mg/l,e.g. 1 to 2 mg/l are sufficient; in other cases higher concentrations,e.g., of the order of 10 to 100 g/l or even up to the limit ofsolubility in the bath can be desirable and advantageous.

One or more of the novel compounds of this invention may be applied totextile materials by conventional finishing techniques such as bythermal induced pad curing so as to incorporate into the textile a flameretardant amount thereof. The compounds of this invention haveadvantages over the flame retardant agents of the prior art in that theymay be used on a variety of textile materials of different chemicalcomposition, and they may be applied by a variety of methods. They maybe applied to materials in either the fiber or fabric form to give flameretarding materials with minimum detectable physical changes in thequality or hand of the textile material.

Products of this invention may be applied to cellulosic materials inseveral ways to give a durable flame retardant treatment. Aqueousmixtures of the products with formaldehyde, urea, trimethylol melamineor other known cellulose crosslinking agents may be applied to cellulosesubstrates with or without the aid of an acidic catalyst by a paddingprocess. The cellulosic material may be immersed in an aqueous solutionof the compounds, trimethylol melamine, and Zn(NO₃)₂.6H₂ O and squeezedon a two roll padder to 70-90% wet weight pick-up. The material is driedat 220°-270° for 1-3 minutes and cured at 300°-370° F for 1-6 minutes ina circulating air oven. The samples are then washed in hot water anddried. The finished samples have a flame retardant add-on of about 5 toabout 40% and preferably about 10 to about 25% by weight.

The flame retardant agents of this invention may be applied to varioustextiles such as cellulosic materials, proteinaceous materials andblends of cellulosic or proteinaceous materials with analogous man-madefibers. By cellulosic materials, applicant intends to embrace cotton,rayon, paper, regenerated cellulose and cellulose derivatives whichretain a cellulose backbone of at least one hydroxy substituent perrepeating glucose unit. By proteinaceous material applicant intends toembrace those textile materials comprising the functional groups ofproteins such as the various animal wools, hairs and furs.

The flame retardant compounds or additives of the invention may beincorporated into resin compositions by known methods. That is, to say,the flame retardant additive may be added to the resin by milling theresin and the additive on, for example, a two-roll mill, or in a Banburymixer, etc., or it may be added by molding or extruding the additive andresin simultaneously, or by merely blending it with the resin in powderform and thereafter forming the desired article. Additionally, the flameretardant may be added during the resin manufacture, i.e., during thepolymerization procedure by which the resin is made, provided thecatalysts, etc., and other ingredients of the polymerization system areinert thereto. Generally, the compounds of this invention may beincorporated into the thermoplastic resin in flame-retarding amounts.

It should be noted that it is also within the scope of the presentinvention to incorporate such ingredients as plasticizers, dyes,pigments, stabilizers, antioxidants, antistatic agents and the like intothe novel composition.

ASTM Test D2863-70, used in accordance with the following examples,generally provides for the comparison of relative flammability ofself-supporting plastics by measuring the minimum concentration ofoxygen in a slowly rising mixture of oxygen and nitrogen that willsupport combustion. The procedure encompasses supporting cylindricaltest specimens 70-200 × 8.0 mm. vertically in a glass tube fitted withcontrolled upward oxygen/nitrogen gas flow. The top of the specimen isignited and oxygen flow is adjusted until it reaches that minimum rateat which the specimen is extinguished before burning 3 minutes or 50 mm.whichever happens first. The oxygen index(n) is then calculated asfollows:

    n,% = (100 × 0.sub.2)/(0.sub.2 +N.sub.2)

wherein 0₂ is the volumetric flow of oxygen, at the minimal rate and N₂is the corresponding volumetric flow rate of nitrogen.

AATCC test method 34-1969, The Vertical Char Test, used in accordancewith the following examples, generally provides for the comparison ofrelative flammability of 2 3/4 inch × 10 inch fabric test specimens whenexposed to a controlled burner flame, under controlled conditions, forperiods of 12.0 and 3.0 seconds. Charred specimens are thereaftersubjected to controlled tearing tests, using tabulated weights, todetermine the average tear length as representing the char length of thefabric. In addition, samples which are wholly consumed by the flame arerated (B) and samples which do not burn are rated (NB). For comparisonpurposes, it should be noted that untreated samples of the fabrics usedin the examples of this case would be consumed by this test.

In all the examples of the application, the following general procedurewas used except when otherwise specifically noted. Padding was done on astandard two roll laboratory padder at a gauge pressure of about 60pounds per square inch in all cases. Drying and curing during processingwere done with a standard laboratory textile circulating air oven.Washing and drying was done in a standard, home, top loading, automaticwasher and dryer.

The following examples are set forth for purposes of illustration onlyand are not to be construed as limitations of the present inventionexcept as set forth in the appended claims. All parts and percentagesare by weight unless otherwise specified.

EXAMPLE 1

Preparation of ##STR10##

A solution of 1,3-bis(dimethylphosphonomethyl) urea (30.43, 0.1 mole) in200 ml of distilled water was placed in a 500 ml round-bottomed,three-necked flask, fitted with reflux condenser, thermometer,thermowatch, magnetic stirring bar and stirrer. The solution wasadjusted to a pH of 1, with oxalic acid.2H₂ O, and maintained by heatingat 80° C for 8 hours. Heating was discontinued and the flask contentsstripped of water solvent in a rotary evaporator (60° C at 20 mm Hg).Purification: The above residue was dissolved in 200 ml of methanol andthe resultant solution treated with methanolic sodium hydroxide to a pHof 9, whereupon the tetrasodium salt of 1,3-bis(dihydrophosphonomethyl)urea separated as a grainy solid. The salt was filtered, washed withseveral portions of cold methanol, followed by dissolution in 200 ml ofdistilled water and treatment with 60 ml concentrated HCl (aqueous). Theaqueous component was stripped exhaustively by a rotary evaporator (50°C at 20 mm of Hg) and the residue dissolved in 200 ml of fresh methanolwhereupon sodium chloride precipitated. The product was filtered, themethanol filtrate was stripped, and the residue dissolved in 100 ml ofdistilled water and subsequently stripped again to an amber oil. Onstanding, the oil solidified to a white waxy solid which analyzes as1,3-bis(dihydrophosphonomethyl) urea containing 2-3 molecular waterunits of hydration. Yield: 85%. Structural verification was made by NMR,infrared spectroscopic and combustion analyses.

EXAMPLE 2

Preparation of ##STR11##

A solution of 1,3-bis(dimethylphosphonomethyl) urea (30.4 g, 0.1 mole)in 200 ml of distilled water was placed in a 500 ml round-bottomed,three-necked flask equipped with thermometer, thermowatch and magneticstirring bar and stirrer. Oxalic acid was added adjusting the pH to 1(0.5 gram), and the solution heated to 50° C. The reaction was monitoredthrough NMR analysis of stripped aliquots withdrawn at 30 minuteintervals. After 1.5 hours, hydrolysis was 50% complete (based on lossof methoxyl groups). Heat was removed, the flask contents stripped andthe residue purified as described in Example 1 above. Twenty-eight gramsof product carrying 2 molecular units of water was obtained representinga 90% yield. Structural identification by NMR, infrared spectroscopicand combustion analysis confirmed the structure.

EXAMPLE 3

Preparation of ##STR12##

A solution of 1,3-bis(diisopropylphosphonomethyl) urea (100 gram, 0.25mole) in 300 ml of distilled water was placed in a 1-literroundbottomed, three-necked flask equipped with a reflux condenser,thermometer, thermowatch and a magnetic stirrer and stirring bar. The pHwas adjusted to 1 with oxalic acid and heat was applied through aheating mantle and Variac. Reaction temperature was maintained at 80° Cfor 3 hours at which time 50% hydrolysis was indicated (NMR was utilizedto monitor reaction, aliquots withdrawn at 30 min. intervals). Theexternal heat source was removed, the flask contents were stripped on arotary evaporator and the residue was purified as described inExample 1. Seventy-five grams (75 g) of product containing 2 molecularunits of water was obtained representing an 82% yield.

EXAMPLE 4

Preparation of ##STR13##

A solution of N-(dimethylphosphonomethyl)-methanesulfonamide (50 gram)in 300 ml of distilled water was treated with 1 ml of HCl (conc.aqueous) and refluxed in a 1 liter round-bottomed flask fitted with areflux condenser, magnetic stirring bar and stirrer, and a heatingmantle. NMR monitoring of aliquots withdrawn at 1-day intervalsindicated 95% hydrolysis after 4 days. The aqueous product was strippedat 50° C and 20 mm of Hg on a rotary evaporator. The viscous residue waspurified as in Example 1. A 75% yield of N-(dihydrophosphonomethyl)methanesulfonamide.3H₂ O was obtained. Structure identification by NMR,infrared spectroscopic analysis and combustion data confirmed thestructure.

EXAMPLE 5

Preparation of ##STR14##

A solution of N-(dimethylphosphonomethyl) acetamide (18.1 gram) in 200ml of distilled water was placed in a 500 ml round-bottomed three-neckedflask fitted with a reflux condenser, thermometer, thermowatch, magneticstirring bar and stirrer and a heating mantle with Variac control. Theflask contents were adjusted to a pH of 1 with oxalic acid and thenmaintained at 60° C for 2 days. The aqueous product solution wasstripped on a rotary evaporator and the residue subjected to thepurification procedure described in Example 1. An 83% yield ofN-(dihydrophosphonomethyl) acetamide containing 2-3 molecular units ofwater was realized. Structure verification by NMR and infraredspectroscopic analysis confirmed the structure.

EXAMPLE 6

Preparation of ##STR15##

Using the reactants and procedure as described in EXAMPLE 4, hydrolysiswas taken to 50% completion, which required 48 hours reflux. The productwas purified according to Example 1. Spectroscopic analysis, NMR andinfrared confirmed the structural identity. A 92% yield of product, asthe dihydrate, was obtained.

EXAMPLE 7

Preparation of ##STR16##

Using the reactants and procedure as described in Example 5, a 16-hourheating at 60° C gave a 50% hydrolysis product. The product was isolatedand purified as described in Example 1. NMR and infrared spectroscopywere used in structure determination. Product containing 2-3 molecularunits of water was obtained in 86% yield.

EXAMPLE 8

Preparation of ##SPC3##

A suspension of 1,3-bis(dimethylphosphonomethyl) benzamide 20.1 gram,0.1 mole) in 200 ml of distilled water was placed in a 500 mlround-bottomed flask equipped with a reflux condenser, stirring bar withstirrer and heating mantle with Variac. Heat was applied, taking theflask contents to reflux. After 3 days, NMR analysis indicated 95%hydrolysis. The product solution was stripped and the residue purifiedaccording to the procedure described in Example 1. Spectroscopicanalysis by NMR and infrared confirmed the structure of product.

EXAMPLE 9

Sequestering ability and efficiencies for the compounds contained in theinvention were determined by titrimetric analysis of solutionscontaining Fe³ ⁺, Cu² ⁺ and Ca² ⁺ : The following procedures were usedin the determinations.

1 Fe³ ⁺

0.5 molar FeCl₃ solution was titrated drop-wise into 50 grams of astirred solution of a given pH containing 0.5 gram of sequestrant.Titration was continued along with simultaneous pH adjustment until aperceptible, permanent haze existed in the solution (end point). Theobservation of haze is facilitated by passing a light beam through thesolution.

Sequestering ability in terms of number of pounds of Fe³ ⁺ sequesteredper 100 pounds of sequestering agent was calculated by multiplying thesequestering efficiency (S.E.) by a factor of 7.1.

2. Cu² ⁺

A 0.5 molar CuCl₂ solution was titrated drop-wise into 100 grams of astirred solution at a given pH containing 50 milligrams of potentialsequestrant (0.05%). Titration was continued with pH adjustment, until aperceptible, permanent haze prevailed in solution.

Sequestering ability in number of pounds of Cu² ⁺ sequestered per 100pounds of sequestering agent was calculated by multiplying thesequestering efficiency (S.E.) by a factor of 22.0.

3. Ca² ⁺

A 0.05 molar CaCl₂ solution was titrated drop-wise into 100 grams of astirred solution at a given pH containing 50 milligrams of sequestrant(0.05%), along with 100 milligrams of sodium carbonate (0.1%) to act asan end-point detector. Titration, with pH adjustment, was continueduntil a perceptible, permanent haze existed in solution.

Sequestering ability in number of pounds of Ca² ⁺ sequestered per 100pounds of sequestering agent was calculated by multiplying thesequestering efficiency (S.E.) by a factor of 10.1.

Results of representative compounds and their sequestering activity aretabulated in Table I.

                                      TABLE I                                     __________________________________________________________________________    Sequestering Efficiencies                                                                Fe.sup.3.sup.+   Cu.sup.2.sup.+   Ca.sup.2.sup.+                   Compound   pH 4                                                                             pH 6                                                                             pH 8                                                                             pH 10                                                                             pH 12                                                                             pH 4                                                                             pH 6                                                                             pH 8                                                                             pH 10                                                                             pH 12                                                                             pH 4                                                                              pH 6                                                                             pH 8                                                                             pH                                                                                pH                 __________________________________________________________________________                                                               12                 1,3-bis(dihydrophos-                                                                     .04                                                                              .08                                                                              .10                                                                              .50 .04 14+                                                                              80 20 .10 .07 19+ 19+                                                                              19+                                                                              3.4 2.1                phonomethyl) urea                                                              ##STR17##                                                                    +          .06                                                                              .08                                                                              .10                                                                              .42 .08  6+                                                                              1.0                                                                              .40                                                                              .32 .25 12+ 12+                                                                              12+                                                                              3.9 1.82                ##STR18##                                                                     ##STR19##                                                                    +          .08                                                                              .12                                                                              .12                                                                              .83 .24  6+                                                                              1.01                                                                             .51                                                                              .51 .51 12+ 12+                                                                              8+ 4.05                                                                              1.51                ##STR20##                                                                    N-(dihydrophosphono-                                                          methyl) methanesulfon-                                                        amide      .80                                                                              .60                                                                              .30                                                                              .08 .08 14+                                                                              1.1                                                                              .50                                                                              .20 .10 19+ 19+                                                                              19+                                                                              2.8 1.3                N-(dihydrophosphono-                                                          methyl) acetamide                                                                        .63                                                                              .51                                                                              .47                                                                              .39 .16  3+                                                                              0.98                                                                             .64                                                                              .53 .22 12+ 12+                                                                              12+                                                                              1.39                                                                              .01                __________________________________________________________________________

EXAMPLE 10

A padding solution was prepared containing 50 parts of1,3-bis(dihydrophosphonomethyl) urea, 49.5 parts water, and 0.5 partTriton X-100 wetting agent.

5.0 oz. per sq. yard cotton sheeting was then padded through thesolution and squeezed to about 95% wet pick-up on a two roll laboratorypadder at 60 lb./in.² gauge pressure. The sheeting was then dried forabout 2.5 minutes at about 200° F. and cured for about 2 minutes atabout 360° F in a circulating air oven. The sheeting was then scoured inan automatic washer with 10 g. of Tide detergent, 50 g. of soda ash, 50g. of sodium perborate and water (13 gal.), tumbled dry, decreasing theweight add-on to about 18.5%. The thus treated sheeting was subjected toAATCC Test 34-1969 and had a char length of 2.125 inches. The oxygenindex of the treated sheeting was 32. The treated sheeting was subjectedto 10 home washes with 50 gr. of Tide and 1/2 cup of Calgon watersoftener in each. The thus washed, treated sheeting had a char length of11/4 inches when subjected to the AATCC Test 34-1969 and an oxygen indexof 32 when subjected to the oxygen index test.

EXAMPLE 11

58 parts of partially hydrolyzed 1,3-bis(diisopropyl phosphonomethyl)urea was made into a pad solution with 41.5 parts water and 0.5 partsTriton X-100 wetting agent.

5.0 oz. per sq. yard cotton sheeting was then padded through thesolution and squeezed to about 94.7% wet pick-up on a two rolllaboratory padder. After drying at about 200° F for about 21/2 minutes,the sheeting was cured at about 360° F for about 5 minutes. The thustreated sheet was scoured and dried as described in Example 10, thetreated sheeting showed a decrease of weight add-on to 13.5%, and anoxygen index of 30. Untreated cotton sheeting had an oxygen index of 20.

EXAMPLE 12

50 parts of N-(dihydrophosphonomethyl) acetamide was mixed with 49.9parts water and 0.1 part Triton X-100 into a pad solution.

5.0 oz. per sq. yard cotton sheeting was padded through the solution andsqueezed to about 90% wet pick-up on the two roll laboratory padder.After drying at about 200° F for about 2.5 minutes and curing at about360° F for about 2 minutes, the treated sheeting was scoured and driedas described in Example 10, showing a 14.7% weight add-on after drying.When tested by the AATCC Test 34-1969 method, the char length was 1.75inches. The oxygen index of the treated sheeting was 32.

EXAMPLE 13

A solution containing 40 parts N-(dihydrophosphonomethyl) methanesulfonamide, 59.9 parts water, and 0.1 parts Triton X-100 wetting agentwas prepared.

5.0 oz. per sq. yard cotton sheeting was padded through the solution andshowed a wet pick-up of about 92.0% after being squeezed through thetwo-roll laboratory padder at 60 lbs./in² gauge pressure. The wet paddedsheeting was dried at about 200° F for about 2.5 minutes, cured at 360°F for about 3 minutes, scoured and dried as described in Example 10. Thethus treated sheeting showed a weight add-on of about 13.8%, a charlength of 2.25 inches when tested by the AATCC Test 34-1969 method, andan oxygen index of 32.

EXAMPLE 14

40.8 parts of partially hydrolyzed, 1,3-bis(dimethylphosphonomethyl)urea was mixed with 58.7 parts water and 0.5 parts Triton X-100 wettingagent.

5.0 oz. per sq. yard cotton sheeting was padded through the solution andsqueezed to about 94.9% wet pick-up on the two roll laboratory padder at60 lb./in² gauge pressure. The sheeting was then dried for about 2.5minutes at about 200° F and cured 10 minutes at about 320° F in acirculating air oven. The treated sheeting was then scoured in anautomatic washer by the method of Example 10, dried and showed a weightadd-on of 11.5%. The treated sheeting had a char length of 11/4 incheswhen tested by the AATCC Test 34-1969 and an oxygen index of 32.

We claim:
 1. A process for sequestering metal ions comprising treatingsaid ions with about 0.001 to about 50 percent aqueous solution of acompound of the formula: ##EQU3## wherein R' is selected from the groupconsisting of ^(-OH), alkyloxy and aryloxy.
 2. The process of claim 1wherein said metal ions are cations having a valence of two or more. 3.The process of claim 1 wherein said metal ions are selected from thegroup consisting of calcium, chromium, copper, nickel, tin, iron,aluminum, cobalt, platinum, palladium, rhodium, iridium, ruthenium,osmium, zirconium, hafnium, the rare earths and the actimides.
 4. Theprocess of claim 1 wherein said compound is added in solution to themetal ions to be sequestered.
 5. The process of claim 1 wherein saidconcentration is from about 0.01 to about 5 percent by weight.
 6. Theprocess of claim 1 wherein said concentration is from about 0.1 to about3 percent by weight.
 7. The process of claim 1 wherein the process ismaintained at a temperature from about 0° to about 100° centigrade. 8.The process of claim 7 wherein said temperature is from about 20° toabout 70° centigrade.
 9. A process of claim 1 wherein R' is OH.
 10. Theprocess of claim 1 wherein R' is alkoxy of 1-6 carbon atoms.
 11. Theprocess of claim 1 wherein at least one R' is an alkyloxy moiety of 1-6carbon atoms.
 12. The process of claim 1 wherein the compound is##STR21##
 13. The process of claim 1 wherein the compound is ##STR22##14. The process of claim 1 wherein the compound is ##STR23##
 15. Theprocess of claim 1 wherein the compound is ##STR24##
 16. The process ofclaim 1 wherein the compound is ##STR25##
 17. The process of claim 1wherein at least one R' is a halogenated aryloxy moiety.